Oct 29, 2013

African American women and white women may not be affected by the same subtypes of the human papillomavirus (HPV), a new study suggests, which is troubling considering currently available HPV vaccines do not protect against the subtypes that were most commonly found in African American women.

Researchers from the Duke University School of Medicine examined the HPV subtypes present in 572 people who were part of the Cervical Intraepithelial Neoplasia Cohort Study, all of whom had abnormal Pap tests. Of those women, 280 were African American and 292 were white.

They looked particularly at HPV subtypes present in the women's cervical intraepithelial neoplasias (CIN), which are abnormalities in the cervix that are considered precursors to cervical cancer. They wanted to see what differences there may be in early CIN (called CIN1) and more advanced CIN (called CIN2 and CIN3).

Among the women with early CIN, HPV subtypes 16, 18, 31, 56 39 and 66 were the most frequently detected among white women. For African American women, though, the HPV subtypes 33, 35, 58 and 68 were most frequently detected.

And among the women with advanced CIN, subtypes 16, 18, 33, 39 and 59 were the most common among white women. For African American women, subtypes 31, 35, 45, 56, 58, 66 and 8 were most frequently detected.

Right now, the currently available HPV vaccine targets HPV subtypes 16 and 18, which are the subtypes that most commonly cause cervical cancer. But "we found a much lower prevalence of HPV 16 and 18 in advanced CIN [CIN2 and 3] from African-American women. Rather, their CIN2 and 3 frequently harbored HPV 31, 35, 45, 56, 58, 66, and 68, all of which are linked to cervical cancer," study researcher Cathrine Hoyo, Ph.D., M.P.H., associate professor in the Obstetrics and Gynecology Department at Duke, said in a statement.

Hoyo also noted that a vaccine targeting seven other cancer-linked HPV subtypes is currently in phase 3 clinical trials.